4 On the left is the OE and on the right is the LED unit. As you can see the LED unit has a short pigtail lead with a three-prong plug that matches the plug on the back of the OE light. Also notice the die-cast finned aluminum housing on the backside of the LED unit. The LED circuit board generates heat and the fins help dissipate the heat so that LEDs will operate properly and at their rated output. If the LEDs were to get too hot the light output would be diminished.